(1) Field of the Invention
The present invention relates to a process for fusion-bonding of resins, which comprises fusion-bonding a powdery or filmy thermoplastic resin to a paper or plastic plate to form a thermoplastic resin layer thereon.
(2) Description of the Prior Art
Heating methods customarily used for thermally softening or fusion-bonding resins include a heat transfer heating method in which a resin is caused to fall in contact with a heat source and a non-contact heating method in which a resin is not caused to fall in contact with a heat source but is heated by, for example, ultrasonic heating or high frequency heating. These methods have merits and demerits and an appropriate method is selected according to the intended use and object.
For example, when even a slight contamination is not desired, the contact method is not preferred, but this method is advantageous in that the equipment is relatively small in size and is simple in structure. The non-contact ultrasonic or high frequency heating method is advantageous in that a resin is not contaminated at all, but is disadvantageous in that the size of the heating apparatus is large and the maintenance thereof is very trouble-some.